Polyesterurethanes stabilized with imino-oxazines

ABSTRACT

POLYESTER BASED POLYMERIC COMPOSITIONS ARE STABILIZED AGAINST HYDROLYSIS BY ADDING TO SAID POLYESTER BASED POLYMERIC COMPOSITIONS A STABILIZING AMOUNT OF A TETRAHYDRO1,3-OXAZINE. THE PREFERRED TETRAHYDRO-1,3-OXAZINES HAVE THE FORMULA   R-(N=C&lt;(-O-CH2-CH2-CH2-N(-R&#39;&#39;)-)X   WHEREIN R AND R&#39;&#39; ARE SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC, CYCLOALIPHATIC OR AROMATIC RADICALS AND X IS 1 OR 2.

United States Patent Int. Cl. C08g 51/60 US. Cl. 26045.8 NZ 6 ClaimsABSTRACT OF THE DISCLOSURE Polyester based polymeric compositions arestabilized against hydrolysis by adding to said polyester basedpolymeric compositions a stabilizing amount of a tetrahydro-1,3-oxazine. The preferred tetrahydro-1,3-oxazines have the formula R'Nc N R -I I on, o I I CHZ- on wherein R and R are selected from thegroup consisting of aliphatic, cycloaliphatic or aromatic radicals and xis 1 or 2.

This application is a division of application Ser. No. 531,093 filedMar. 2, 1966 and now US. Pat. No. 3,479,- 351.

This invention relates to tetrahydro oxazines, particularly totetrahydro-1,3-oxazines, more particularly to tetrahydro-Z-imino-1,3-oxazines and to the stabilization of ester-containingcompositions therewith.

Heretofore it has been recognized in an article entitledAnlagerungsrecktionen mit Epoxyden by Klaus Gulbins and Karl Hamann,Berichte, Volume 94, page 3287 (1961), that the reaction of 1,2-alkyleneoxide with a carbodiimide should be expected to result in the formationof iminooxazolidines. This article, however, points out that this is notthe case and iminooxazolidines do not result due to the fact that theyare unstable and are converted immediately to cyclic ureas.

In addition, various organic materials, particularly polyesters, aredecomposed in the presence of oxygen and moisture. Some of the productsresulting from the hydrolysis of polyesters in the presence of moistureare acid materials which, in turn, accelerate further decomposition ofthe polyesters.

Since the polyurethanes prepared from polyesters and polyisocyanates areuseful as coatings, foams and elastomers, it is essential that productsnormally resulting from the hydrolysis of these polyesters in thepresence of moisture be substantially eliminated. It has been suggestedthat various stabilizers such as carbodiirnides may be incorporated inpolyesters and polyurethanes, to retard the formation of thesehydrolytic products.

Therefore, it is an object of this invention to provide a method forpreparing organic oxazine derivatives. It is another object of thisinvention to provide a method for stabilizing polyesters againsthydrolysis. It is still another object of this invention to provide amethod for stabilizing compositions containing polyesters againsthydrolysis. It is a further object of this invention to provide apolyester composition stabilized against hydrolysis. It is a stillfurther object of this invention to provide coatings, foams andelastomers containing stabilizers which have improved age and weatherresistant properties. A still further object of this invention is toprovide polyurethanes which are resistant to deterioration.

3,640,952 Patented Feb. 8, 1972 The foregoing objects and others whichwill become apparent from the following description are accomplished inaccordance with the invention, generally speaking, by providing a methodfor preparing tetrahydro oxazine derivatives having the formula RII RI/0 RII RII wherein R is the residue obtained by removing at least one NCOgroup from an organic isocyanate, R is an organic group having from 1 to15 carbon atoms, R" which may be the same or different, is eitherhydrogen, halogen or organic groups having from 1 to 10 carbon atoms andx is an integer equal to the number of NCO groups removed from R.

Examples of organic groups such as, aliphatic, cycloaliphatic, andaromatic groups represented by R and R above are alkyl, aryl orcycloalkyl radicals, of which phenyl, a-naphthyl, fl-naphthyl,a-anthryl, 3-anthryl, 'yanthryl: o-tolyl, m-tolyl, p-tolyl, 2,3-xylyl,2,4-xylyl, 2,5- xylyl, 2,6-xylyl, 3,4-xylyl, 3,5-xylyl, o-cumenyl,m-cumenyl, p-cumenyl, mesityl, o-ethylphenyl, m-ethylphenyl,p-ethylphenyl, 0-, mand p-tertiary butylphenyl, 2,6-ditertiarybutylphenyl, o-, mand p-ethoxyphenyl, o-, mand p-tert. butoxyphenyl andthe like, are examples of aryl radicals. Alkyl radicals are, forexample, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,sec-butyl, tert.'butyl, n-pentyl and various positioned isomers thereof,such as, for example, l-methylbutyl, Z-methylbutyl, 3-methylbutyl,1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl,l-ethylpropyl and the like; corresponding straight and branched chainisomers of hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl,tridecyl, tetradecyl, hexadecyl and the like. Examples of cycloalkylradicals which may be employed are, cyclopropyl, cyclobutyl, o-, mandp-isopropyl cyclohexyl, o-, mand p-tert.butyl cyclohexyl, cycloheptyl,cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl and thelike.

In other words, the invention relates to a process for preparingtetrahydro-1,3-oxazine derivatives having the above formula by reactingcarbodiirnides or polymeric carbodiirnides with trimethylene oxide orderivatives of trimethylene oxide at a temperature of from about 50 C.to about 250 0., preferably from about C. to about 200 C. in thepresence of a catalyst. Even though a solvent is not essential to thisreaction, it is preferred that the reaction be conducted in the presenceof an inert organic solvent.

Polycarbodiimides having the following representative formula wherein Ris a bivalent organic radical and y is an integer greater than 1, may bereacted with 1,3-a1kylene Oxides such as trimethylene oxide orderivatives of trimethylene oxide to form polymerictetrahydro-l,3-oxazines.

Organic diisocyanates which may be uesd in the formation of thepolymeric carbodiirnides include toluene 2,4-diisocyanate, m-phenylenediisocyanate, 4-chloro-1,3- phenylene diisocyanate, 4,4'-biphenylenediisocyanate, 1,5- naphthalene diisocyanate, tetramethylenediisocyanate, decamethylene diisocyanate, 1,4-cyclohexylenediisocyanate, 4,4-methy1ene-dicyclohexylene diisocyanate and 1,5-tetrahydronaphthylene diisocyanate. Mixtures of two or more of theseorganic diisocyanates may be used, in which case the bivalent organicradical R in the above formula will not be the same in each recurringunit. It is also to be understood that isocyanate-terminated polymersmay be used to form these carbodiimides, in which case the carbodiimidewill have more than 15 carbon atoms and the substantially linearpolymers will have a plurality of intralinear carbodiimide linkages.Here again, it is to be understood that mixtures of two or moreditferent isocyanate-tenminated polymers may be used, in which case thebivalent organic radical R in the above formula will not be the same ineach recurring unit.

Likewise, compounds containing more than two free isocyanate groups mayalso be used in the formation of polymers containing a plurality ofcarbodiimide linkages. In this case, the resulting organic carbodiimidewill be a high molecular weight, substantially cross-linked polymer.Representative compounds containing more than two free isocyanategroups, which may be used include 2,4,6-triisocyanato toluenep-isocyanatophenyl-Z,4-diisocyanatophenyl ether, and compounds which areprepared from trifunctional reactants. It is readily apparent that anyof a wide variety of organic compounds containing more than two freeisocyanate groups may be used in the formation of compounds havingpolycarbodiimide linkages.

Although a solvent is not essential in the preparation of tetrahydrooxazines from the reaction of a carbodii-mide with trimethylene oxide orsubstituted trimethylene oxide, it is preferred that the reaction beconducted in the presence of an inert organic solvent. Solvents whichmay be employed are for example aliphatic, cycloaliphatic, or aromatichydro carbons, preferably those with to 16 carbon atoms such as,heptane, isooctane, cyclohexane, benzene, toluene or halogenatedhydrocarbons, containing from 1 to carbon atoms, for example, carbontetrachloride, chloroform, ethylene chloride, trichlorofluoromethane,tetrachloroethane, chlorobenzene, trichlorobenzene fluorobenzene or openor cyclic ethers, such as, dioxane, tetrahydrofuran, dibutyl ether,dimethyltetrahydrofuran or dialkyl ethers of ethylene glycol and dialkylethers of diethylene glycol and so forth. It is preferred that dioxane,tetrahydrofuran or dialkyl ethers of ethylene glycol and dialkyl ethersof diethylene glycol be employed as solvents in the formation of theseoxazines.

Although it is not essential, it is highly preferred that a suitablecatalyst be used in carrying out this reaction and that the reaction bemaintained at a temperature less than about 250 C. for a period of from1 to 8 hours, preferably from 1 to 3 hours.

Catalysts which may be used to accelerate the formation of thetetrahydro oxazines are, for example, tertiary amines, includingN,N-dimethylaniline, 1-methy1-4 (dimethylaminoethyl)piperazine, N-ethylethenylidine, N,N, N',N-tetramethyl ethylene diamine, triethyl azmine,2,4,6- tri(dimethylaminomethyl)benzene, N-ethyl morpholine,Z-methyl-piperazine and the like; alkali metal hydroxides includingsodium hydroxide, potassium hydroxide, lithium hydroxide and the like;tetraethyl ammonium bromide and the like. It is preferred that thetrialkyl amine catalysts be used.

It is to be understood that the particular amount of catalyst used willdepend to a large extent on the reactivity of the specific catalyst.Since these: catalysts accelerate the formation of the tetrahydrooxazines from carbodiimides and trimethylene oxide, catalytic amounts ofthese catalysts should be used, such as 0.01 to 35.0 parts of catalystper 100 parts of carbodiimide.

Any suitable carbodiimide may be used in the practice of this inventionto prepare tetrahydro oxazines such as, for example, diisopropylcarbodiimide, dicyclohexyl carbodiimide, methyl tertiary-butylcarbodiimide, tertiary butyl phenyl carbodiimide,tetrarnethylene-bis-diisobutyl carbodiimide, N-dimethyl amino propyltertiary butyl canbodiimide, the 'monoglycol ether ofhydroxyphenyltertiary butyl carbodiimides,

diphenyl carbodiimide,

dinaphthyl carbodiimide, 2,2'-dimethyl-diphenyl carbodiimide,2,2'-diisopropyl-diphenyl carbodiimide,

4 2-dodecyl-2'-n-propyl-diphenyl carbodiimide,2,2'-diethoxy-diphenyl,carbodiimide, 2-dodecyl-2-ethyldiphenylcarbodiimide, 2,2-dichloro-diphenyl carbodiimide,2-ethyl-2'-isopropyl-diphenyl carbodiimide 2,6,2',6-tetraethyl-diphenylcarbodiimide, 2,6,2',6-tetraethyl-3,3'-dichloro diphenyl carbodiimide,2,6,2',6-tetrasecondary-butyl-diphenyl carbodiimide,2,6,2',6'-tetraisopropyl-3,3-dinitro-dipheny1 carbodiimide,Z-ethyl-cyclohexyl-Z-isopropyl-phenyl carbodiimide,2,4,5,2',4,6-hexaisopropyl-diphenyl carbodiimide,2,2'-diethyl-dicyclohexyl carbodiimide, 2,6,2',6'-tetraisopropyldicyclohexyl carbodiimide, 2,6,2,6-tetraethyl-dicyclohexyl carbodiimideand 2,2'-dichloro-dicyclohexyl carbodiimide, 2,2-dicarbethoxy diphenylcarbodiimide, 2,2'-dicyano-diphenyl carbodiimide and the like.

Any suitable carbodiimide having more than one carbodiimide group mayalso be used, such as, those described in US. Pat. 2,941,966.

The trimethylene oxide or substituted trimethylene oxide may be used inequivalent proportions or in excess of the quantity of the carbodiimideused.

The reactants are inserted into a reaction vessel containing a solventwhich is non-reactive with the reactants and the reaction product. Thereactants are heated to a temperature of from about C. to about 250 C.and maintained at this temperature for from about 1 to about 3 hours orlonger. The reaction mass is then cooled and the product is separated bystandard techniques such as crystallization or distillation.

The tetrahydro-1,3-oxazines may be prepared by conventional meansstarting from 'y-hydroxy propyl amine as represented by the followingequations:

wherein R and R are organic radicals.

The removal of hydrogen sulfide can be affected according to the J. Am.Chem. Soc. 47, 1981 (1925) and the University of Kansas Science Bulletinvol. 20, No. 6, 161 (1931). Desulfurizati'on agents which may beemployed are, for example, mercuric oxide, lead oxide, ethylenechlorohydrin in potassium hydroxide or a mixture of sodium hydroxide andchlorine.

The 'y-hydroxy propyl amines may be prepared by a number ofconventionally known techniques, for example, those disclosed in the J.Am. Chem. Soc. 42, 1720 (1920), or J. Am. Chem. Soc. 76, 2789 (1954).

Any suitable organic amine may be used in the formation of the'y-hydroxy propyl amines such as, for example, aliphatic and aromaticprimary amines which may be defined by the following structural formula:

wherein R represents an aliphatic radical having from 1 to 20 carbonatoms, an aromatic radical having from 6 to 18 carbon atoms, andcycloaliphatic radical having from 5 to 15 carbon atoms as well assubstituted aliphatic, aromatic and cycloaliphatic radicals.

Amines which conform to the above are well known in the art.Illustrative of these aliphatic amines are the primary alkyl amines suchas methylamine, ethylamine, n-propylamine, isopropylamine,n-butylarnine, isobutylamine, sec.-butylamine, tert.butylamine,amylamine,

isoamylamine, Z-aminopentane, n-hexylamine, n-octylamine, n-decylamine,n-dodecylamine, n-tetradecylamine. Illustrative of aromatic amines areaniline, toluidine, 2,4- xylyldine, o-anisidine, p-anisidine and soforth. Illustrative be used in the interchange reaction. The organicisocyanates and corresponding isothiocyanates contemplated herein, arefor example, methyl isocyanate, ethyl isocyanate, propyl isocyanate,isopropyl isocyanate, allyl of cycloaliphatic amines are cyclohexylamine, methylisocyanate, butyl isocyanate, isobutyl isocyanate, sec.-cyclohexyl amine, ethylcyclohexyl amine, propylcyclobutyl isocyanate,tert.-butyl isocyanate, amyl isocyanate, hexyl amine, butylcyclohexylamine and so forth. Ex- 3-methoxypropylisocyanate,tetradecylisocyanate,chloroamples of alkoxy amines are methoxy benzylamine, decyl isocyanate,dodecyl isocyanate, hexadecyl isocyaethoxybenzylamine,propoxybenzylamine and so forth. nate, octadecyl isocyanate, 1isocyanato-octadecene-9,

Organic isothiocyanates which may be reacted with 1 phenyl isocyanate,cyclohexyl isocyanate, o-chlorophenyl amino alcohols are, for example,methyl isothiocyanate, isocyanate, m-chlorophenyl isocyanate,p-chlorophenyl ethyl isothiocyanate, propyl isothiocyanate, isopropylisoisocyanate, o-toluyl isocyanate, m-toluyl isocyanate, pthiocyanate,allyl isothiocyanate, butyl isothiocyanate, toluyl isocyanate,o-ethylphenyl isocyanate, o-ethoxyisobutyl isothiocyanate, sec-butylisothiocyanate, tert.- phenyl isocyanate, p-ethoxyphenyl isocyanate,2,4-dibutyl isothiocyanate, amyl isothiocyanate, 3-methoxychlorophenylisocyanate, a-naphthyl isocyanate, B-naphpropyl isothiocyanate,tetradecyl isothiocyanate, chlorothyl isocyanate, o-biphenyl isocyanate,o-phe'noxyphenyl decyl isothiocyanate, dodecyl isothiocyanate, hexadecylisocyanate and the like. Among the .polyisothiocyanates isothiocyanate,octadecyl isothiocyanate, l-isothiocyanatowhich are useful are, forexample, trimethylene diisocyaoctadecene-9, phenyl isothiocyanate,cyclohexyl isothionate, hexamethylene diisothiocyanate,butylene-l,3-diisocyanate, o-chlorophenyl isothiocyanate, m-chlorophenylthiocyanate, methylene-bis-4-phenyl diisocy-an-ate, ethylisothiocyanate,p-chlorophenyl isothiocyanate, o-toluyl ene tetraisothiocyanate and thelike. isothiocyanate, lll-tolyl isothiocyanate, P 31 isothio Theinterchange reactions may take place in the ab- 3Ya11? 1te,o'ethylphenyl isothiocy anat?, o'ethoxyphenlfl sence of a solvent;however, it is preferred that the reaclsothlocyanate. P' YPlsothlPcyaflatei tion be conducted in the presence of an organic solventchlorophenyl lsocyanate ?P lsoth}ocyanate which is inert to the oxazinesand the isocyanates. Exnaphthyl oblphenyl lsoihlocyanate amples ofsuitable inert organic solvents are benzene, PhenoXYPhenYllsoihloclanate and hexane, xylene, toluene, naphthalene, dioxane, cyclo-Among the liolylsothlocyagates.whlch are useful hexane, carbontetrachloride, nitrobenzene chlorobenfor example, trlrnethylenednsothiocyan'itlte, hexamethyl- Zena and the like ene diisothiocyanate,butylene-LS-diisot iocyanate, propylene-2,2-diisothiocyanate,cyclohexylene 1,2-diisothio g; i g i t i 'f' i partlcularly cyanate,1,4-phenylene diisothiocyanate, Inethylene-bis- 11.86 H m e S a 1.1Zatmno ester i 4-phenyl diisothiocyanate, ethylene tetraisothiocyanate Honsmay be 9 l q therem by any i a and the Elm technique, such as dissolving1n the ester compositlon,

New derivatives of previously prepared tetrahydro-1,3- or adding to oneof the reactants befofe they wlth oxazines may be synthesized aninterchange reaction the esters. In the event the polyester is reactedwith oras illustrated by the following general equations: ganicpolyisocyanates to form polyurethanes, the ozazines wherein R, R and Rare the same as defined in Formula 1; R' may be aliphatic,cycloaliphatic or aromatic, Z is a divalent radical selected from thegroup consisting of oxygen and sulfur and x is an integer of from 1 to4.

Where interchange reactions occur when using the tetrahydro-l,3-oxazinesas stabilizing agents in polymeric systems employing isocyanates, it isparticularly advantageous to first prepare derivatives by the aboveinterchange reaction in order to remove RNCZ, where RNCZ is so volatilethat it may be obnoxious or dangerously toxic.

Since this reaction results in an equilibrium condition, it is necessarythat the isocyanate thus formed or isothiocyanate (RNCZ) be removedimmediately in order to substantially complete the reaction. Whenpolyisocyanates are used and depending on the amount of oxazine presentin the mixture, the interchange reaction may take place with one or moreof the NCO groups present.

Any suitable organic isocyanate or isothiocyanate may may be added afterthis reaction takes place in the dissolved state, by rolling, milling,stirring, or any other suitable technique.

Any compound containing ester linkages it may be stabilized againsthydrolytic degradation in accordance with this invention. Thus any estercomposinamic acid, benzene tricarboxylic acid, adipic acid, 6- aminocaproic acid, succinic acid, suberic acid, sebacic acid, oxalic acid,methyladipic acid, glutaric acid, pimelic acid, azelaic acid, phthalicacid, terephthalic acid, isophthalic acid, malonic acid, maleic acid,fumaric acid, citraconic acid, itaconic acid, etc. with alcohols, suchas methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol,n-butyl alcohol, isobutyl alcohol, secondary butyl alcohol, tertiarybutyl alcohol, amyl alcohol, hexyl alcohol, octyl alcohol, decylalcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearylalcohol, allyl alcohol, methallyl alcohol, crotyl alcohol,2-propyn-1-ol, oleyl alcohol, geraniol, citronellol, linalool, diacetonealcohol, ethylene glycol monoethyl ether, cyclohexanol, naphthenicalcohols, benzyl alcohol, tolyl alcohol, phenylethyl alcohol,octadecylbenzyl alcohol, ethylene glycol, propylene glycol, 1,4butanediol, 1,3 butanediol, 1,5-- pentanediol, 1,6-hexanediol,bis-(hydroxymethyl)-cyclohexane, diethylene glycol, 2,2 dimethylpropylene glycol, 1,3,6 hexanetriol, trimethylol propane,pentaerythritol, sorbitol, glycerine and the like. The method ofstabilizing compositions containing ester groups is applicable not onlyto monoesters but also to polyesters in accordance with the compoundslisted above having a functionality greater than 1. For example, whereany of the dior polycarboxylic acids are reacted with the diorpolyhydric alcohols, a polyester having more than one ester group, ofcourse, will result.

Other compositions containing polyester resins as a reactive componentor in admixture can also be stabilized by the process of this invention.For example, compositions such as polyester amides and polyesterurethanes can be stabilized. The reaction product of any of the carboxyterminated or hydroxyl terminated esters set forth above can be reactedwith a suitable isocyanate to prepare a polyurethane. In the preparationof polyesteramides, the reaction of a carboxylic acid, an alcohol and anamine can be carried out simultaneously or in steps in the manner setforth for the preparation of polyesteramides. Amino alcohols and aminoacids can be used in the preparation of polyesteramides. The importantfeature is, however, that any composition containing ester groups can bestabilized against hydrolysis by the introduction thereof of atetrahydro oxazine within the formula set forth above.

Any suitable organic polyisocyanate may be used to prepare polyesterurethanes which may be stabilized in accordance with this invention,such as, for example, those more particularly set forth above.

Any suitable amino compound can be used to prepare polyesteramides suchas, for example, hexamethylene diamine, ethylene diamine, propylenediamine, butylene diamine, cyclohexylene diamine, phenylene diamine,tolylene diamine, xylylene diamine, 4,4 diamino-diphenylmethane,naphthylene diamine, aminoethyl alcohol, aminopropyl alcohol, aminobutylalcohol, aminobenzyl alcohol, aminoacetic acid, aminopropionic acid,aminobutyric acid, aminovaleric acid, aminophthalic acid, aminobenzoicacid and the like. Of course, the amino compounds may be reacted eithersimultaneously with the ester forming components or sequentiallytherewith.

It is also within the scope of this invention that naturally occurringesters may be stabilized against hydrolysis and aging in accordance withthis invention such as, for example, castor oil, coconut oil, corn oil,cottonseed oil, horse fat oil, lard oil, wool fat, Japan wax, muttontallow, beef tallow, neats foot oil, palm oil, peanut oil, carnauba wax,spermaceti, beeswax, rapeseed oil, soya bean oil, whale oil, sperm oiland the like. Further, any compositions containing ester groups as Wellas unsaturation may be stabilized in accordance with this invention.Such compositions may be formed by polymerization, condensation or acombination of both. Any of these unsaturated carboxylic acids mentionedabove may be used in the preparation of such polyesters. Furtherexamples of such compositions include polyester resins of polymerizablemonomers and unsaturated polyesters, for example, those of fumaricormaleic acid as well as ethylene vinyl ester copolymers, acrylic andmethacrylic acid ester polymers and/ or their copolymers with vinylesters, fluorinated acrylic esters and their copolymers, copolymers ofacrylonitrile and acrylic acid esters such as methylacrylate and thelike. The invention is particularly applicable to the stabilizaton ofpolyesters used in the manufacture of synthetic resins which may resultin the form of lacquers, foils and coatings, fibers, foam materials,elastomers or casting resins for molded elements.

Any of the tetrahydro oxazines within the generic formula set forthabove may be used to stabilize any of the polyester compositionsdescribed herein. The tetrahydro oxazines should be used in astabilizing amount, however. It is preferred that an amount of 0.005 toabout 10 parts per parts of polyester be used.

The invention is further illustrated but not limited by the followingexamples in which parts and percentages are by weight unless otherwisespecified.

EXAMPLE 1 Preparation of tetrahydro-2-phenylimino-3-phenyl- 1,3-oxazineAbout 97 parts (0.5 mol) of diphenylcarbodiimide are added to anautoclave containing about 206 parts of dioxane, about 18 parts oftriethylamine and 34.8 parts (0.6 mol) of trimethylene oxide. Thereaction mass is heated to a temperature between about and, 180 C. andmaintained at this temperature for 5 hours. After cooling the dioxane isremoved by vacuum distillation. and the resulting product isrecrystallized from isopropyl alcohol. The product is identified byinfra-red spectrum as tetrahydro-2-phenylimino-3-phenyl-1,3-oxazine.

EXAMPLE 2 A mixture of about 484 parts (5.2 mols) of aniline, 246 parts(2.6 mols) of 1-chloro-3-propanol and 250 parts of anhydrous sodiumcarbonate is added to a reactor and refluxed for from 3 to 4 hours. Thereaction product is filtered and the residue washed with ether. Thefiltrate is distilled and after the excess aniline is removed a viscouslemon-colored liquid is recovered which turns red on standing. Thisproduct boils at a temperature of about 192 C. under 30 mm. pressurewhich is identified as 'y-hydroxypropyl aniline. Approximately 302 parts(2 mols) of the 'y-hydroxypropyl aniline is reacted with approximately270 parts (2.0 mols) of phenylisothiocyanate in approximately 310 partsof dry dioxane. The react on temperature increased to about 50 C. andupon standing the product crystallized. These crystals are separatedfrom the reaction mass by filtration, dried and identified asdiphenyl-hydroxypropylthiourea. Approximately 330 parts 1.29 mols) ofthis thiourea is mixed with about 616 parts of dry benzene containingapproximately 419 parts of mercuric oxide with agitation. The reactionmass is heated to boiling and the water distilled oif as an azetropicmixture with benzene and collected to determine when the reaction issubstantially complete. The solvent is removed in vacuo and the productis recrystallized from isopropyl alcohol. The product obtained isidentical to that obtained in Example 1.

EXAMPLE 3 a temperature of about C. for a period of 5 hours.

At the end of this time, the reaction mixture is cooled and transferredto a distillation system where an excess of trimethylene oxide andtriethylamine are recovered by fractional distillation. The dioxane isstripped in vacuo and the solid residue recrystallized from isopropylalcohol. The product is identified by infra-red spectrum astetrahydro-2-cyclohexylimino 3 cyclohexyl 1,3 oxazine.

EXAMPLE 4 Into a stainless steel l-liter stirred autoclave is introduced141 parts of bis-(p-ethoxyphenyl)-carbodiimide, 204 parts of drydioxane, 18 parts of triethylamine and 35 parts of trimethylene oxide.The solution is heated with stirring at a temperature of between about160 and 180 C. for about 5 hours. At the end of this time, the reactionmixture is cooled and transferred to a distilling flask where excesstrimethylene oxide and triethylamine are recovered by fractionaldistillation. The dioxane is then stripped in vacuo and the residuerecrystallized from isopropyl alcohol and identified astetrahydro-Z-p-ethoxyphenylimino-3-p-ethoxyphenyl-1,3-oxazine.

EXAMPLE 5 Into a stainless steel l-liter stirred autoclave is introduced77 parts of dibutyl carbodiimide, 204 parts of dry dioxane, 18 parts oftriethylamine and 35 parts of trimethylene oxide. The solution is heatedwith stirring at a temperature between about 160 and 180 C. for 5 hours.At the end of this time, the reaction mixture is cooled and transferredto a distilling flask where excess trimethylene oxide and triethylamineare recovered by fractional distillation. The dioxane is stirpped invacuo and the solid residue is recrystallized from isopropyl alcohol.The crystalline product is identified from infra-red spectrum astetrahydro-2-butylimino-3-butyl-1,3-oxazine.

EXAMPLE 6 About 20 parts of poly(2,4-tolylene carbodiimide) and about200 parts of tet-rahydrofuran are introduced into a 1-liter stainlesssteel stirred autoclave along with about 5 parts of triethylamine andabout parts of trimethyl ene oxide. The solution is heated with stirringto a temperature between about 170 and 190 C. for about 5 hours. At theend of this time, the reaction mixture is cooled and transferred to adistillation system, where excess trimethylene oxide, triethylamine andtetrahydrofuran are removed. The residue is identified as a polymerictetrahydro-1,3-oxazine product of poly(2,4-tolylene carbodiimide)EXAMPLE 7 Into a 1-liter three neck flask is charged 126 parts (0.5 mol)tetrahydro-Z-phenylimino-3-phenyl-1,3-oxazine, 62.5 parts (0.25 mol) of4,4'-diphenylmethane diisocyanate and 400 parts by volume of drydecalin. The flask is equipped with a thermometer, a mechanical stirrerand a fractionating column with a variable reflux head equipped forvacuum distillation. The exchange reaction is conducted at 100 to 150 C.with agitation, the boiling temperature being controlled by varying thevacuum. Phenyl isocyanate along with some decalin is removed as overheadas the reaction progresses. As soon as no further phenyl isocyanate isevolved, all but approximately 100 parts by volume of the decalin isremoved by distillation in vacuo and the reaction mass is allowed tocool. The product which separates as a white solid is filtered and driedin vacuo. From the infra-red spectrum and the elemental analysis, theproduct is found to have the following structure:

I Q-N C N-Q-C-Q-N C I l I l I cu o H o I l I 1 CH2 CH; CH, on,

10 EXAMPLE 8 In the same equipment as Example 7 is charged about 126parts (0.5 mol) tetrahydro-2-phenylimino-3-phenyl- 1,3-oxazine, 43.5parts of 2,4-toluene diisocyanate and about 400 parts by volume of drydecalin (dried over sodium). The mixture heated to a temperature betweenand C. with agitation, the boiling temperature being controlled byvarying the vacuum. Phenyl isocyanate along with some decalin is removedas overhead as the reaction progresses. As soon as no additional phenylisocyanate is evolved, all but approximately 100 parts by volume of thedecalin is removed by distillation in vacuo. The product which separatesout as a solid, is filtered and dried. From infra-red analysis theproduct is found to have the following structure:

at. N,,@ /\-N.C.N 1.2... 2 crr int; 3H

EXAMPLE9 Approximately 604 parts (4 mols) of 'y-hydroxypropyl anilineprepared in accordance with Example 2 is reacted with about 384 parts(2.0 mols) of phenylene diisothiocyanate in about 310 parts of drydioxane. The reaction temperature is not allowed to go over 50 C. Theproduct crystallized and is sepaarted from the reaction mass byfiltration and dried. Approximately 494 parts (1.0 mol) of the productproduced above is then mixed with about 616 parts of dry benzenecontaining about 325 parts of mercuric oxide. The reaction mass isheated to boiling with agitation and the water distilled ofi. as anazeotropic mixture with benzene and collected to determine when thereaction is substantially complete. The reaction product is filtered andthe residue washed with hot benzene. The benzene is removed by vacuumdistillation and the product is identdified by the conventionalanalytical techniques and found to have the following formula:

EXAMPLE 10 Approximately 604 parts (4 mols) or 'y hydroxypropyl anilineprepared in accordance with Example 2 is reacted with about 564 parts(2.0 mols) of 4,4'-diisothiocyanatodiphenyl methane in approximately 310parts of dry dioxane. The reaction temperature is not allowed to go over50 C. Upon cooling, crystals are formed which are separated from thereaction mass by filtration and dried. Approximately 584 parts 1.0 mol)of the crystalline product obtained above are mixed with about 616 partsof dry benzene containing approximately 325 parts of mercuric oxide. Thereaction mass is heated to boiling with agitation and the waterdistilled off as an azeotropic mixture with benzene and is collected inorder to determine when the reaction is complete. The benzene is thenremoved by vacon, on;

EXAMPLE 11 A solution containing approximately 438 parts (6 mols) ofn-butyl amine and about 174 parts (3 mols) of trimethylene oxide andabout 75 parts of water are heated in an autoclave at 150 C. for about18 hours. The crude reaction product is recovered by distillation. Afterdrying over potassium hydroxide pellets the product is redistilledyielding a 3-butylamino-1-propanol, boiling point 106 to 108 C. (16mm.).

Approximately 262 parts (2 mols) of the 3-butylaminol-propanol arereacted with about 270 parts (2 mols) of phenylisothiocyanate in about310 parts of dry dioxane. The reaction temperature is not allowed torise above 50 C. After cooling the product crystallized and is separatedfrom the reaction mass by filtration and dried. Approximately 262 partsof this crystalline product are mixed with about 600 parts of drybenzene containing about 325 parts of mercuric oxide with agitation. Thereaction mass is heated to boiling and the water distilled off as anazeotropic mixture with benzene. The reaction mass is filtered and theprecipitate washed with hot benzene. The benzene is removed by vacuumdistillation and the resulting product is recrystallized from isopropylalcohol. The product is identified astetrahydro-2-phenylimino-3-butyl-1,3-oxazine.

EXAMPLE 12 About 1 part of tetrahydro-Z-phenylimino-3-phenyl-1,3-oxazine prepared in accordance with the description of Example 1 isdissolved in about 100 parts of a hydroxyl polyester having a molecularweight of about 2000 and an hydroxyl number of about 57, which isprepared by reacting adipic acid with diethylene glycol and trimethylolpropane. About 10 parts of an isomeric mixture of 80 percent 2,4- and 20percent 2,6-toluylene diisocyanate is added to this mixture which isthen cast onto a Teflon coated tray to a thickness of about 4; inchwhere it is permitted to remain for about 2 hours at about 110 C.Identical samples are prepared without the addition of thetetrahydro-2-phenylimino-3-phenyl-1,3-oxazine of Example 1. The polymersare placed on a 1-inch screen over a steam bath at about 100 C. Theunmodified polymers softened after a few hours and completely failedafter about 5 days.

Those containing the additive in accordance with this invention did notsoften even after five days of exposure.

In a similar manner the following derivatives of tetrahydro-1,3-oxazineshave been incorporated in polyesters with substantially the sameresults: 2-cyclohexylimino-3- cyclohexyl-2,p-ethoxyphenylimino-3,p-ethoxypheny1-, 2-butylimino-B-butyl-1,3-oxazine and polymeric oxazines ofpoly(2,4-tolylene carbodiimide) EXAMPLE 13 To baout 100 parts of thepolyester of Example 12 are added about 0.67 part oftetrahydro-Z-phenylimino-3- phenyl-1,3-oxazine prepared in accordancewith Example 1. To this mixture is added about parts of an isometricmixture consisting of about 80 percent 2,4-toluylene diisocyanate andabout percent of 2,6-toluylene diisocyanate.

CH; CH;

The mixture which is one typically used in the prepaartion of printingrollers is cast in to a test sample. The test sample is subjected tosteam at 100 C. This sample failed after about 144 hours. In comparison,a similar sample containing none of the additives set forth above failedafter about 90 hours.

EXAMPLE 14 The procedure of Example 13 is followed with the exceptionthat approximately 4 parts of the tetrahydro oxazine described inExample 1 is added to aboutv 100 parts of the polyester. A test sampleprepared using this stabilized polyester exhibited no signs of failureeven after a period of about 144 hours on a steam bath.

EXAMPLE 15 To about 100 parts of the polyester described in Example 12is added 1.15 parts of a compound having the formula:

Q N C N Q N C I. N Q I I l 1 H20 0 0 CH; I I

H;C CH; H O CH;

which is then reacted with about 10 parts of an isomeric mixtureconsisting of about percent 2,4-toluylene diisocyanate and about 20percent 2,6-toluylene diisocyanate. The reaction mixture which is onetypically used in the prepaartion of printing rollers is cast into atest sample. The test sample is subjected to saturated steam atapproximately 100 C. This sample appeared to fail after about 144 hours.In comparison, a similar sample containing none of the additive setforth above failed after a little over hours.

EXAMPLE 1-6 The procedure of Example 15 is followed with the exceptionthat 3.47 parts of the compound having the formula represented inExample 15 is added to the polyester. A test sample prepared using thisstabilizer exhibited no signs of failure even after 144 hours on a steambath.

EXAMPLE 17 To about parts of a hydroxyl terminated polyester obtainedfrom the reaction of about 10 mols of adipic acid and about 11 mols of1,4-butane diol and having an hydroxyl number of 56 and an acid numberless than 1 is added to about 9 parts of 1,4-butane diol and about 40parts of 4,4'-diphenylmethane diisocyanate. The reaction mixture isimmediately cast into a heated plate maintained at a temperature ofabout C. where it is permitted to solidify. Upon solidification, thematerial is removed from the plate and tested for elongation, elongationset, tensile and tear strength. The sample is then subjected to steam at15 pounds per square inch gauge for a period of about 16 hours and thentested again. To each of three 100 part samples of the polyester reactedas above, are added the quantities of the compound of Example 1indicated in the following table. The test data both before and afterthe steam test are set forth:

It is of course to be understood that any of the tetrahydIo-1,3-oxazinesmentioned above may be used in the stabilization of any of thepolyesters set forth above. Also, any of the carbodiimides may be usedin the preparation of the oxazines in accordance with this invention andmay be substituted into the examples for those specifically set forthherein.

Although the invention has been described in considerable detail in theforegoing for the purpose of illustration, it is to be understood thatsuch detail is solely for this purpose and that variations can be madeby those skilled in the art without departing from the spirit and scopeof the invention.

What is claimed is:

1. A polyester based polymeric composition stabilized against hydrolysiscomprising a polyesterurethane and a stabilizing amount of atetrahydro-l,3-oxazine having the formula CH J 14 about 0.005 part toabout 10 parts of tetrahydro-1,3- oxazine are present per 100 parts ofpolyester based polymer.

3. The stabilized composition of claim 1 wherein R is a phenyl radical,R is a phenyl radical and x is 1.

4. The stabilized composition of claim 1 wherein R' is a phenyl radical,R is a divalent phenylene radical and x is 2.

5. The stabilized composition of claim 1 wherein R is a phenyl radical,R is a divalent diphenylmethane radical and x is 2.

6. The stabilized composition of claim 1 wherein R is a cyclohexylradical, R is a cyclohexyl radical and x is 1.

References Cited UNITED STATES PATENTS 2,817,663 12/1957 Conlon et al260244 2,974,120 3/1961 Miller 260-45.8 2,995,540 I 8/1961 Duennenbergeret al. 26045.8 3,479,351 11/1969 Metzger, Ir. 260-246 DONALD E. CZAJA,Primary Examiner R. A. WHITE, Assistant Examiner US. Cl. X.R.

260-25 BB, T, 398.5, 468 R

